scholarly journals Excitation to defect-bound band edge states in two-dimensional semiconductors and its effect on carrier transport

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Dan Wang ◽  
Dong Han ◽  
Damien West ◽  
Nian-Ke Chen ◽  
Sheng-Yi Xie ◽  
...  
Keyword(s):  
Carrier Transport ◽  
Band Edge ◽  
Two Dimensional ◽  
Edge States

scholarly journals Multi-shaped strain soliton networks and moiré-potential-modulated band edge states in twisted bilayer SiC

RSC Advances ◽  
2021 ◽  
Vol 11 (39) ◽  
pp. 24366-24373
Author(s):  
Dawei Kang ◽  
Zheng-Wei Zuo ◽  
Zhaowu Wang ◽  
Weiwei Ju
Keyword(s):  
Twist Angle ◽  
Layered Materials ◽  
Degree Of Freedom ◽  
Band Edge ◽  
Two Dimensional ◽  
Edge States

Tuning the interlayer twist angle provides a new degree of freedom to exploit the potentially excellent properties of two dimensional layered materials.

scholarly journals Anomalous properties of the band-edge states in large two-dimensional photonic quasicrystals

2007 ◽  
Vol 76 (16) ◽  
Author(s):  
Yun Lai ◽  
Zhao-Qing Zhang ◽  
Chi-Hou Chan ◽  
Leung Tsang
Keyword(s):  
Band Edge ◽  
Two Dimensional ◽  
Edge States ◽  
Photonic Quasicrystals

Experimental demonstration of directional acoustic radiation based on two-dimensional phononic crystal band edge states

2007 ◽  
Vol 90 (8) ◽  
pp. 083509 ◽  
Author(s):  
Manzhu Ke ◽  
Zhengyou Liu ◽  
Pei Pang ◽  
Chunyin Qiu ◽  
Degang Zhao ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Phononic Crystal ◽  
Band Edge ◽  
Two Dimensional ◽  
Edge States ◽  
Experimental Demonstration

scholarly journals Epitaxial Dimers and Auger-Assisted De-Trapping in PbS Quantum Dot Solids

2019 ◽  
Author(s):  
Rachel H. Gilmore ◽  
Yun Liu ◽  
Wenbi Shcherbakov-Wu ◽  
Nabeel Dahod ◽  
Elizabeth Lee ◽  
...  
Keyword(s):  
Solar Cells ◽  
Quantum Dot ◽  
Carrier Transport ◽  
Open Circuit ◽  
Charge Carriers ◽  
Transient Absorption Spectroscopy ◽  
Band Edge ◽  
Edge States ◽  
Trap States ◽  
Trap State

Electronic trap states limit the overall power conversion efficiency of quantum dot (QD) solar cells by inhibiting charge carrier transport and reducing the open-circuit voltage. Here, we explore the dynamic interaction of charge carriers between band edge states and sub-band trap states using broadband transient absorption spectroscopy. In monodisperse arrays of 4-5 nm diameter PbS QDs, we observe an optically active trap state ~100-200 meV below the band edge that occurs at a frequency of 1 in ~2500 QDs. Uncoupled QD solids with oleic acid ligands show trap-to-ground-state recombination that resembles Auger recombination. In electronically coupled QD solids, we observe entropically-driven uphill thermalization of trapped charge carriers from the trap state to the band edge <i>via</i> two distinct mechanisms: Auger-assisted charge transfer (~35 ps) and thermally activated hopping (~500 ps). Photophysical characterization combined with atomistic simulations and high-resolution transmission electron microscopy suggest that these states arise from epitaxially fused pairs of QDs – rather than electron or hole traps at the QD surface – offering new strategies for improving the efficiency of QD solar cells.

A design rule for two-dimensional van der Waals heterostructures with unconventional band alignments

2020 ◽  
Vol 22 (5) ◽  
pp. 3037-3047 ◽  
Author(s):  
Yuan Si ◽  
Hong-Yu Wu ◽  
Ji-Chun Lian ◽  
Wei-Qing Huang ◽  
Wang-Yu Hu ◽  
...  
Keyword(s):  
Van Der Waals ◽  
Interlayer Coupling ◽  
Band Alignment ◽  
Band Edge ◽  
Design Rule ◽  
Two Dimensional ◽  
Edge States ◽  
Van Der Waals Heterostructures ◽  
Band Alignments

A feasible rule to design unconventional band alignment by inducing the hybridization of band-edge states via interlayer coupling.

scholarly journals Epitaxial Dimers and Auger-Assisted De-Trapping in PbS Quantum Dot Solids

2019 ◽  
Author(s):  
Rachel H. Gilmore ◽  
Yun Liu ◽  
Wenbi Shcherbakov-Wu ◽  
Nabeel Dahod ◽  
Elizabeth Lee ◽  
...  
Keyword(s):  
Solar Cells ◽  
Quantum Dot ◽  
Carrier Transport ◽  
Open Circuit ◽  
Charge Carriers ◽  
Transient Absorption Spectroscopy ◽  
Band Edge ◽  
Edge States ◽  
Trap States ◽  
Trap State

Electronic trap states limit the overall power conversion efficiency of quantum dot (QD) solar cells by inhibiting charge carrier transport and reducing the open-circuit voltage. Here, we explore the dynamic interaction of charge carriers between band edge states and sub-band trap states using broadband transient absorption spectroscopy. In monodisperse arrays of 4-5 nm diameter PbS QDs, we observe an optically active trap state ~100-200 meV below the band edge that occurs at a frequency of 1 in ~2500 QDs. Uncoupled QD solids with oleic acid ligands show trap-to-ground-state recombination that resembles Auger recombination. In electronically coupled QD solids, we observe entropically-driven uphill thermalization of trapped charge carriers from the trap state to the band edge <i>via</i> two distinct mechanisms: Auger-assisted charge transfer (~35 ps) and thermally activated hopping (~500 ps). Photophysical characterization combined with atomistic simulations and high-resolution transmission electron microscopy suggest that these states arise from epitaxially fused pairs of QDs – rather than electron or hole traps at the QD surface – offering new strategies for improving the efficiency of QD solar cells.

Theoretical realization of two-dimensional Dirac/Weyl line-node and traversing edge states in penta-X2Y monolayers

2021 ◽  
Vol 23 ◽  
pp. 101057
Author(s):  
Lirong Wang ◽  
Lei Jin ◽  
Guodong Liu ◽  
Ying Liu ◽  
Xuefang Dai ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Edge States ◽  
Line Node

scholarly journals Schwarzian quantum mechanics as a Drinfeld-Sokolov reduction of BF theory

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Fridrich Valach ◽  
Donald R. Youmans
Keyword(s):  
Quantum Mechanics ◽  
Partition Function ◽  
Gauge Group ◽  
Path Integral ◽  
Coadjoint Orbits ◽  
Two Dimensional ◽  
Edge States ◽  
Class Constraint ◽  
Action Functional ◽  
Bf Theory

Abstract We give an interpretation of the holographic correspondence between two-dimensional BF theory on the punctured disk with gauge group PSL(2, ℝ) and Schwarzian quantum mechanics in terms of a Drinfeld-Sokolov reduction. The latter, in turn, is equivalent to the presence of certain edge states imposing a first class constraint on the model. The constrained path integral localizes over exceptional Virasoro coadjoint orbits. The reduced theory is governed by the Schwarzian action functional generating a Hamiltonian S1-action on the orbits. The partition function is given by a sum over topological sectors (corresponding to the exceptional orbits), each of which is computed by a formal Duistermaat-Heckman integral.

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